SANTA CRUZ -- After more than a week of jury selection, trial began Friday morning for Richard Chavez, who is charged with murdering his girlfriend.

Deanna Dudley died after being struck in the head on Feb. 28, 2010 at the Felton house where the couple lived.

Both sides said in opening statements that the case doesn't represent a "whodunit" or as defense attorney Mark Briscoe said, "a search for the six-fingered man." There is no dispute that Chavez killed Dudley; at issue is whether he intended to and what the circumstances were.

Prosecutor Michael Gilman emphasized the brutal nature of Dudley's injuries, starting his opening remarks by showing the jurors the large black flashlight she was fatally struck with.

"This is the flashlight that that man used to brutally kill Deanna Dudley," Gilman said, pointing to Chavez. "He used it to crush her skull as she lay on the ground. Blood started rushing, filling her hair. She was face down. He hit her again."

The blows caused blood to shoot out across the room, splattering the wall, he said.

Gilman said that prosecutors will present evidence that Chavez has a history of domestic abuse, and that he had hurt Dudley before. Dudley was not a perfect person, he said. Both she and Chavez had issued with alcohol, and Dudley also used prescription drugs recreationally.

"But she did not deserve to have her life taken away by that man," Gilman said. "She did not deserve to be silenced."

Gilman painted a picture of Chavez as a cold-hearted, abusive individual who wouldn't be bothered to call 911 as Dudley lay dying.

"Murder is what the defendant committed," Gilman told jurors. "Murder. Not self-defense, not some reduced crime, not a crime of passion."

Briscoe disputes the prosecution's characterization of his client, whom he said performed first-aid on Dudley while begging the woman he loved not to die and doing all he could to stop the bleeding.

Dudley and Chavez were longtime friends, kindred souls, Briscoe said.

"Their friendship had no bounds," he said. "These were two people doing everything they could for each other."

After more than a decade of friendship, their relationship moved from platonic to romantic in the months before her death. Briscoe said Dudley's prescription drug habit became more of a problem, she started hitting her two children and the police had to make frequent trips to her home. He said she once knocked Chavez out cold by hitting him with a heavy ashtray.

When she died, she had a blood alcohol content of 0.17 and six prescription drugs were found in her bloodstream, Briscoe said, and the night of the death, the two argued over watching the Winter Olympics.

Dudley came at Chavez with the flashlight, and a struggle ensued, he said. As she lie on the floor bleeding, "Richard was down on his knees, begging her to stay alive." He apologized over and over, asking her to stay with him.

"One person lost her life, the other lost his best friend, his lover, his partner because of his actions," Briscoe said. "This is a tragedy. This is not a murder."

The prosecution's first witness, sheriff's deputy Shawna Hernandez, began testifying late Friday morning about what the blood and other evidence she found at the scene. She's expected to resume testimony Monday.